Class TransformedMap<K,V>
- java.lang.Object
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- org.apache.commons.collections4.map.AbstractIterableMap<K,V>
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- org.apache.commons.collections4.map.AbstractMapDecorator<K,V>
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- org.apache.commons.collections4.map.AbstractInputCheckedMapDecorator<K,V>
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- org.apache.commons.collections4.map.TransformedMap<K,V>
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- Type Parameters:
K
- the type of the keys in this mapV
- the type of the values in this map
- All Implemented Interfaces:
java.io.Serializable
,java.util.Map<K,V>
,Get<K,V>
,IterableGet<K,V>
,IterableMap<K,V>
,Put<K,V>
- Direct Known Subclasses:
TransformedSortedMap
public class TransformedMap<K,V> extends AbstractInputCheckedMapDecorator<K,V> implements java.io.Serializable
Decorates anotherMap
to transform objects that are added.The Map put methods and Map.Entry setValue method are affected by this class. Thus objects must be removed or searched for using their transformed form. For example, if the transformation converts Strings to Integers, you must use the Integer form to remove objects.
Note that TransformedMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using
Collections.synchronizedMap(Map)
. This class may throw exceptions when accessed by concurrent threads without synchronization.This class is Serializable from Commons Collections 3.1.
- Since:
- 3.0
- See Also:
TransformedSplitMap
, Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected Transformer<? super K,? extends K>
keyTransformer
The transformer to use for the keyprivate static long
serialVersionUID
Serialization versionprotected Transformer<? super V,? extends V>
valueTransformer
The transformer to use for the value-
Fields inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
map
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Constructor Summary
Constructors Modifier Constructor Description protected
TransformedMap(java.util.Map<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)
Constructor that wraps (not copies).
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description protected V
checkSetValue(V value)
Override to transform the value when usingsetValue
.protected boolean
isSetValueChecking()
Override to only return true when there is a value transformer.V
put(K key, V value)
Note that the return type is Object, rather than V as in the Map interface.void
putAll(java.util.Map<? extends K,? extends V> mapToCopy)
private void
readObject(java.io.ObjectInputStream in)
Read the map in using a custom routine.static <K,V>
TransformedMap<K,V>transformedMap(java.util.Map<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)
Factory method to create a transforming map that will transform existing contents of the specified map.static <K,V>
TransformedMap<K,V>transformingMap(java.util.Map<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)
Factory method to create a transforming map.protected K
transformKey(K object)
Transforms a key.protected java.util.Map<K,V>
transformMap(java.util.Map<? extends K,? extends V> map)
Transforms a map.protected V
transformValue(V object)
Transforms a value.private void
writeObject(java.io.ObjectOutputStream out)
Write the map out using a custom routine.-
Methods inherited from class org.apache.commons.collections4.map.AbstractInputCheckedMapDecorator
entrySet
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Methods inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
clear, containsKey, containsValue, decorated, equals, get, hashCode, isEmpty, keySet, remove, size, toString, values
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Methods inherited from class org.apache.commons.collections4.map.AbstractIterableMap
mapIterator
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Field Detail
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serialVersionUID
private static final long serialVersionUID
Serialization version- See Also:
- Constant Field Values
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keyTransformer
protected final Transformer<? super K,? extends K> keyTransformer
The transformer to use for the key
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valueTransformer
protected final Transformer<? super V,? extends V> valueTransformer
The transformer to use for the value
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Constructor Detail
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TransformedMap
protected TransformedMap(java.util.Map<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)
Constructor that wraps (not copies).If there are any elements already in the collection being decorated, they are NOT transformed.
- Parameters:
map
- the map to decorate, must not be nullkeyTransformer
- the transformer to use for key conversion, null means no conversionvalueTransformer
- the transformer to use for value conversion, null means no conversion- Throws:
java.lang.NullPointerException
- if map is null
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Method Detail
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transformingMap
public static <K,V> TransformedMap<K,V> transformingMap(java.util.Map<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)
Factory method to create a transforming map.If there are any elements already in the map being decorated, they are NOT transformed. Contrast this with
transformedMap(Map, Transformer, Transformer)
.- Type Parameters:
K
- the key typeV
- the value type- Parameters:
map
- the map to decorate, must not be nullkeyTransformer
- the transformer to use for key conversion, null means no transformationvalueTransformer
- the transformer to use for value conversion, null means no transformation- Returns:
- a new transformed map
- Throws:
java.lang.NullPointerException
- if map is null- Since:
- 4.0
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transformedMap
public static <K,V> TransformedMap<K,V> transformedMap(java.util.Map<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)
Factory method to create a transforming map that will transform existing contents of the specified map.If there are any elements already in the map being decorated, they will be transformed by this method. Contrast this with
transformingMap(Map, Transformer, Transformer)
.- Type Parameters:
K
- the key typeV
- the value type- Parameters:
map
- the map to decorate, must not be nullkeyTransformer
- the transformer to use for key conversion, null means no transformationvalueTransformer
- the transformer to use for value conversion, null means no transformation- Returns:
- a new transformed map
- Throws:
java.lang.NullPointerException
- if map is null- Since:
- 4.0
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writeObject
private void writeObject(java.io.ObjectOutputStream out) throws java.io.IOException
Write the map out using a custom routine.- Parameters:
out
- the output stream- Throws:
java.io.IOException
- if an error occurs while writing to the stream- Since:
- 3.1
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readObject
private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, java.lang.ClassNotFoundException
Read the map in using a custom routine.- Parameters:
in
- the input stream- Throws:
java.io.IOException
- if an error occurs while reading from the streamjava.lang.ClassNotFoundException
- if an object read from the stream can not be loaded- Since:
- 3.1
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transformKey
protected K transformKey(K object)
Transforms a key.The transformer itself may throw an exception if necessary.
- Parameters:
object
- the object to transform- Returns:
- the transformed object
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transformValue
protected V transformValue(V object)
Transforms a value.The transformer itself may throw an exception if necessary.
- Parameters:
object
- the object to transform- Returns:
- the transformed object
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transformMap
protected java.util.Map<K,V> transformMap(java.util.Map<? extends K,? extends V> map)
Transforms a map.The transformer itself may throw an exception if necessary.
- Parameters:
map
- the map to transform- Returns:
- the transformed object
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checkSetValue
protected V checkSetValue(V value)
Override to transform the value when usingsetValue
.- Specified by:
checkSetValue
in classAbstractInputCheckedMapDecorator<K,V>
- Parameters:
value
- the value to transform- Returns:
- the transformed value
- Since:
- 3.1
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isSetValueChecking
protected boolean isSetValueChecking()
Override to only return true when there is a value transformer.- Overrides:
isSetValueChecking
in classAbstractInputCheckedMapDecorator<K,V>
- Returns:
- true if a value transformer is in use
- Since:
- 3.1
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put
public V put(K key, V value)
Description copied from interface:Put
Note that the return type is Object, rather than V as in the Map interface. See the class Javadoc for further info.- Specified by:
put
in interfacejava.util.Map<K,V>
- Specified by:
put
in interfacePut<K,V>
- Overrides:
put
in classAbstractMapDecorator<K,V>
- Parameters:
key
- key with which the specified value is to be associatedvalue
- value to be associated with the specified key- Returns:
- the previous value associated with
key
, ornull
if there was no mapping forkey
. (Anull
return can also indicate that the map previously associatednull
withkey
, if the implementation supportsnull
values.) - See Also:
Map.put(Object, Object)
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